Power-assisted velocipedes such as mopeds have been available for many years. In such vehicles, torque is applied to the rear wheel by a pedal sprocket or by the shaft of a motor or by both of those means with one supplementing the other. However, these prior power-assisted velocipedes have tended to be quite complex and, therefore, expensive. In this, they require a large capacity motor and various belts and other linkages in order to enable the motor and pedal sprocket to operate in conjunction with one another. Also, the motor units on such power-assisted velocipedes have tended to be rather large and bulky so that the product overall is commensurately large and cumbersome.